I am just downloaded the full retail Assassin's Creed 3 from eShop. It will be on internal memory at this point as its 17GB and I had 25GB avail. However, this won't be the last game I download as I try to take advantage of the 10% return and simply don't want discs laying around.

So, in a month or so I will likely need to connect my 1TB drive to WiiU (after I get a new one to replace it on my PC), but I'm curious how large digital games play off of the HDD.

Does it play as good as your disc games? Any lagging online, etc?

Please share your experience in any detail. THANKS!

I downloaded nsmbu and it plays just fine. Also kens rage 2. I do not recommend kens rage 2, but it also plays with no problems.

On an external HDD or the internal storage?

Internal storage.

I haven't played much online with the games on my hard drive but they were just fine to my experience. I have NSMBU, Trine 2, and Assassins Creed III. It's just fine.

i bought Tekken Tag 2 on Eshop which is about 15 GB and it is running flawlessly on my 400GB drive.
i have had no troubles downloading to it and loading from it.
it's pretty old drive so i am probably going to get a new bigger one in the near future but i am pleased with it's performance.
in March i am planning on buying lego city digitally i think because of the premium bonus thing(need credit for virtual console upgraded versions)